This invention relates to a so called pinch roller type paper feeding automatic drafting machine in which idle rollers are placed in pressure contact with drive rollers to feed paper in a reciprocating direction, and more particularly to a paper feeding machine for the automatic drafting machine. The pinch roller type paper feeding automatic drafting machine is disclosed in U.S. Pat. No. 4,384,298. The conventional pinch roller type paper feeding device disclosed in the foregoing patent, as shown in FIG. 8, is constructed in such a way that the paper 6 is sandwiched by the drive rollers 2 and the pressure rollers 4 by a pinch roller mechanism, and the paper 6 is fed in the X-coordinate axial direction by the rotary drive of the drive rollers 2 a writing implement 10 is fed in the Y coordinate axial direction on the guide plate 8, and a predetermined drawing is carried out on the paper on the guide plate 8.
Also, as shown in FIG. 6 and FIG. 7, an X-motor 14 is connected to an underlay roller 12, and the paper is sandwiched by the surfaces of the drive rollers 2, 2a at both end portions of the underlay roller 12 and the pressure rollers 16, 18. The drawing is carried out by the writing implement 10 on the paper 6 above the underlay roller 12.
In the case of the construction shown in FIG. 8 the writing implement 10 contacts the paper 6 on the guide plate 8 exerting a predetermined writing pressure. When the paper 6 is fed in -X direction by the pinch roller mechanism, a blocking force is generated against the shifting of the paper 6 by the writing pressure of the writing implement, and the portion 6a of the paper 6 between the writing implement 10 and the pinch roller mechanism floats as shown in the drawing. When the paper 6 floats, the writing implement 10 is hooked on the floating portion 6a of the paper 6 which causes the paper to tear or an error to occur in the drawing. An object of this invention is to provide the floating of the paper 6 between the writing implement and the pinch roller mechanism.
Also, in case of the construction shown in FIG. 6, at the time of drawing, when the tip of the writing implement 10 resiliently contacts the paper 6 on the underlay roller 12, a feeding transfer speed of the portion of the paper 6 is deteriorated by the frictional force between the tip of the writing implement 10 and the paper 6 when compared with a feeding transfer speed of the portion of the paper 6 which is sandwiched by the pinch rollers. Because of this deterioration of the speed, the paper 6 is distorted which causes an error in the drawing that is undesirable. An object of this invention is to eliminate the delay of feeding of the portion of the paper to be fed by the pinch roller mechanism which is in resilient contact with the writing implement.